1. Field of the Invention
The present invention relates to a semi-automatic gun, in which part of the gas evolved upon detonation of a cartridge in the breech of the gun is used to actuate a reloading mechanism. In particular the invention relates to a rifle having a reloading mechanism of the type which includes a cylinder fixed to the barrel of the rifle and encircling a portion of a cartridge magazine which extends parallel to the barrel, the cylinder and the encircled portion of the magazine forming an annular chamber which is closed at one end and open at the other end, at least one gas duct leading from the barrel to the said annular chamber, and a tubular piston slidable along the annular chamber between the magazine and the said cylinder and defining a power chamber between itself and the closed end of the annular chamber.
2. Prior Art
Known actuating devices of this type for reloading mechanisms suffer from a number of disadvantages. For example, high temperature gases entering the annular chamber impinge on the wall of the magazine and can cause damage which may be sufficiently severe as to result in the piercing of the magazine wall. Moreover, the kinetic energy of the gases evolved upon detonation of different types of cartridge varies widely and the actuating device for the reloading mechanism must be such that it will satisfactorily operate with low power cartridges while nevertheless not be damaged by high power cartridges.